Tried playing multiplayer CoD: Black Ops 2, only to find out you can't connect?

If it cannot sustain a connection.

1) Run the game as an admin using administrator mode (right click the game -> run as administrator)2) Disable your firewall (software and hardware / nat firewalls)3) Enable gaming mode on your wireless / wired router4) Open the following ports: 4500; 3478-3479; 3658 (TCP/UDP)

Boom! You can now connect to the CoD Black Ops II server for multiplayer and matchmaking.

Hopefully that was able to help you fix your unable to connect Call of Duty: Black Ops II issue! It certainly was able to solve the problem for us!